ARS | Publication request: CITRIC ACID TREATMENT OF FLAX, COTTON AND BLENDED NONWOVEN MATS FOR COPPER ION ABSORPTION

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2006
Publication Date: February 1, 2007
Citation: Marshall, W.E., Akin, D.E., Wartelle, L.H., Annis, P.A. 2007. Citric acid treatment of flax, cotton and blended nonwoven mats for copper ion absorption. Industrial Crops and Products. 26:8-13

Interpretive Summary: Heavy metal from storm water runoff is a growing concern that now includes state and federal mandates for containment. Researchers at ARS and university institutes collaborated on a project using natural fiberflax and cotton non woven mats to absorb heavy metals from water. Data showed that flax at 100% or 75% blend (with 25% cotton) was the most effective mat for copper ion absorption. Results are important in that a potential new use for flax fiber was identified and also that storm water run off could be controlled with natural fiber products, possible resulting in new biomass products.

Technical Abstract: The removal of metal ions from polluted water and wastewater with biodegradable, natural products is an area of current interest in the environmental arena. The objective of this study is to determine whether nonwoven mats made of biodegradable, natural fibers of flax and cotton can be used for remediation of a ubiquitous pollutant of water and wastewater, namely, copper ion. Nonwoven mats manufactured with flax or cotton fiber and flax/cotton fiber blends were treated with citric acid in order to enhance the amount of negative charge on the mats and improve their ability to sequester copper ion. The treated mats were monitored for changes in copper ion adsorption and fabric strength and compared to non-treated mats and process control mats. The results show that mats made from 100% flax and 75%/25% flax/cotton blends were similar to each other and significantly better at copper ion absorption copper ion than 100% cotton or 50%/50% flax/cotton blended nonwoven mats. Citric acid treatment, however, diminished mat strength compared to untreated mats for all samples; strength was similar for all treated nonwoven mats after correction for variable mat thickness. Treated flax fiber mats and flax/cotton fiber mats represent a potentially fast and convenient method for removal of metal ions from water and wastewater streams at an approximate cost of $ 1.40 / m2 of mat.